There are increasing possible uses of devices, such as laser catheters, in surgery due to the growing number of different structural designs of laser catheters and their distal end regions. For instance, laser catheter tips are known which can, in particular, be employed in bypass surgery and which are especially distinguished by the fact that the cross section of the distal end of the laser catheter at which the light exists is completely composed of optical fibers. Such catheters are referred to, by way of illustration, as “full multifiber catheters”.
With the aid of the aforementioned type of catheter, techniques for laser-aided anastomosis (surgical joining of two hollow organs, such as, attaching an additional blood-carrying channel (bypass) to a bloodchannel artery whose flow cross section is narrowed by deposits) are known, which permit bypass surgery without interrupting the blood flow in the main artery. For instance, the ELANA (Excimer Laser Assisted Nonocclusive Anastomosis) operating technique, developed by neurosurgeon C. A. F. Tulleken and described in U.S. Pat. No. 5,964,750 and EP 0 750 476, deals with a surgical technique for creating an arteriotomy in which a catheter creates a geometrically exactly predefined hole in the wall of a vessel and at the same time ensures that separated remains of the vessel do not stay in the blood stream. U.S. Pat. No. 5,964,750 is incorporated herein by reference in its entirety.
First a bypass vessel is connected to the outer circumference of the vessel to be treated. Through this bypass vessel, a laser catheter tip, which is designed elastically at the distal end, is inserted and positioned within the bypass vessel, onto the outer wall of a pressurized intracorporal vessel to be treated. The catheter is provided with a perforated member disposed at its distal end, capable of transmitting vacuum suction which is created in the lumen. The catheter creates an opening in the pressurized intracorporal vessel by cutting along a closed line (generally a circle) and holding on to the vessel wall cut out by vacuum (or low pressure) suction. Through this opening, part of the blood flow can be diverted through the bypass vessel around the obstruction in the treated vessel.
In addition to the great advantage of being able to conduct bypass surgery without interrupting the pressurized intracorporal vessel, which is especially vital in bypass surgery in the brain, this surgical technique has several drawbacks. For example, as the vessel wall is under pressure and is put under additional tension by surgical suturing and by the vacuum suction within the catheter, the tension is such that as the vessel wall is being cut, the vessel wall can cause the cut-out piece of vessel wall to be pulled sideways. The resulting movement of the vessel wall can cause the cut to be ineffective, and thus the cut tissue remains attached. Additionally, the movement can also cause fluid (such as blood, or gases in other circumstances) to be drawn into the lumen, thereby increasing the pressure within the lumen and thus reducing the force with which the vessel wall is being held to the perforated member. Thus, in some of these cases, the cut is not complete and a piece of vessel wall (a “flap”) remains attached to the rest of the vessel wall and retained rather than adhering to the perforated member and being retrieved out of the body with the catheter.
Thus, it is desirable that a device for creating arteriotomies be designed to reduce the incidence of retained flaps.